Birds posses narrow wings in colder climate related to :

Options

A. (A) Bergmann's
B. (B) Jordan's Rule
C. (C) Ranch's Rule
D. (D) Allen's Rule

Answer

To answer the question regarding why birds possess narrow wings in colder climates, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why birds in colder climates have narrow wings compared to those in warmer climates.

2. **Identifying Relevant Ecological Rules**: We need to look for ecological rules that explain the adaptation of birds in colder climates. The options provided include Bregman's rule, Jordan's rule, Rancher's rule, and Ellen's rule.

3. **Evaluating Bregman's Rule**: Bregman's rule states that warm-blooded animals in colder areas tend to be larger in size compared to those in warmer areas. This rule does not specifically address the wing structure of birds, so it is not relevant to our question.

4. **Evaluating Jordan's Rule**: Jordan's rule pertains to cold-water fishes, stating that they tend to have more vertebrae than warm-water fishes. Again, this rule does not relate to birds or their wing structure, making it irrelevant.

5. **Evaluating Rancher's Rule**: Rancher's rule specifically states that birds in colder areas have narrower wings compared to those in warmer areas. This directly addresses our question, indicating that this is the correct rule that explains the adaptation of birds in colder climates.

6. **Evaluating Ellen's Rule**: Ellen's rule discusses the extremities of mammals, stating that they are shorter in colder climates compared to those in warmer climates. This rule does not pertain to birds or their wings, making it irrelevant to our question.

7. **Conclusion**: Based on the evaluation of the rules, the correct answer is Rancher's rule, which explains that birds in colder climates possess narrow wings.

### Final Answer:
Birds possess narrow wings in colder climates related to **Rancher's rule**.

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